1. Field of the Invention
The present invention relates to a rotary table with a rotatable table, and more particularly to a brake structure, for a rotary table, that clamps a rotatable table to stop the rotation of the rotatable table.
2. Description of the Related Art
A general rotary table includes a rotatable index table, a stationary member (main body) rotatably supporting the rotatable table, a driving mechanism driving the rotatable table, and a brake mechanism clamping the rotatable table so as not to rotate the rotatable table. An example of the brake mechanism is disclosed in Japanese Unexamined Patent Application Publication No. 2009-248244 (FIG. 1). This brake mechanism includes a cylindrical sleeve coaxially provided on the back surface of the rotatable table and a hydraulic chamber formed on the non-rotatable stationary member that faces the inner peripheral surface of the sleeve. Feeding oil into and applying pressure on the hydraulic chamber deform a thin wall, which is part of the stationary member and defines the hydraulic chamber, so as to bulge out and abut against the sleeve.